Effects of Strains of Saccharomyces cerevisiae and Incubation Conditions  on the In vitro Degradability of Yeast and Roughage

Ando, S.; Nishiguchi, Y.; Hayasaka, K.; Yoshihara, Y.; Takahashi, J.; Iefuji, H.

doi:2005.18.3.354

Article

Animal Breeding and Genetics

Asian-Australasian Journal of Animal Sciences 2005;18(3): 354-357.
https://doi.org/10.5713/ajas.2005.354 Published online April 20, 2005.

Effects of Strains of Saccharomyces cerevisiae and Incubation Conditions on the In vitro Degradability of Yeast and Roughage

S. Ando, Y. Nishiguchi, K. Hayasaka, Y. Yoshihara, J. Takahashi, H. Iefuji

Abstract

The in vitro degradability of yeast and the effect of yeast on the in vitro degradability of forage may differ in terms of the specific yeast strains or their incubation conditions. Thus in experiment 1, two strains of sake yeast (strainK7 and strainK9) and one strain of bakers` yeast (KY5649) were incubated in an aerobic condition. In experiment 2, aerobically or anaero bically incubated K7 was used for investigating the in vitro degradability of yeast, the effect of yeast on the in vitro degradability of forage, and the degradability of yeast by pepsin and pronase treatment. The in vitrodegradability of bakers` yeast was significantly (p<0.05) higher than those of sake yeasts. The in vitro degradability of anaerobically incubated yeast was significantly (p<0.01) higher than that of aerobically incubated yeast. The degradability of bakers` yeast by pepsin treatment was significantly (p<0.01) higher than that of the sake yeasts. The degradability of bakers` yeast by pronase treatment was slightly higher than that of the two sake yeasts, while the degradability of anaerobically incubated yeast by both enzymes, respectively, was significantly (p<0.01) higher than that of aerobically incubated yeast. The degradability of forages was increased significantly (p<0.05) by the addition of yeasts. The degradability of roughage by sake yeast tended to be higher than that by the bakers` yeast. The degradability of roughage was significantly (p<0.05) higher by anaerobically incubated yeast than by aerobically incubated yeast. Given the above results, it seems that in vitro degradability of yeast and the magnitude of the increment of roughage degradation differ among the yeast strains and their incubation conditions.

Keywords: Yeast; Degradability; Rice-straw; Italian-ryegrass; Sorghum Incubation-condition